Fabrication of high quality Cu2SnS3 thin film solar cell with 1.12% power conversion efficiency obtain by low cost environment friendly sol-gel technique

Cu2SnS3 (CTS) is an emerging ternery chalcogenide material with great potential application in thin film solar cells. We present here high quality Cu2SnS3 thin films using a facile spin coating method. The as deposited films of CTS were sulphurized in a graphite box using tubular furnace at 520 degrees C for 60 min at the rate of 2.83 degrees C min(-1) in argon atmosphere. X-ray diffraction (XRD) and Raman spectroscopy studies confirm tetragonal phase and absence of any secondary phase in sulphurized CTS thin films. X-ray photoelectron spectroscopy (XPS) demonstrates that Cu and Sn are in +1 and +4 oxidation state respectively. Surface morphology of CTS films were analyzed by field emission scanning electron microscope and atomic force microscope (AFM), which revealed a smooth surface with roughness (RMS) of 6.32 nm for sulphurized CTS film. Hall measurements confirmed p-type conductivity with hole concentartion of sulphurized CTS thin film is of 6.5348 x 10(20) cm(-3). UV-vis spectra revealed a direct energy band gap varies from 1.45 eV to 1.01 eV for as-deposited and sulphurized CTS thin film respectively. Such band gap values are optimum for semiconductor material as an absorber layer of thin film solar cell. The CTS thin film solar cell had following structure: SLG/FTO/ZnO/CTS/Al with short circuit current density of (J(sc)) of 11.6 mA cm(-2), open circuit voltage (V-oc) of 0.276 V, active area of 0.16 cm(-2), fill factor (FF) of 35% and power conversion efficiency of 1.12% under AM 1.5 (100 mW cm(-2)) illumination in simulated standard test conditions.